Problem with Drag&Drop virtual file in .NET app

I've downloaded the example app from blog: https://dlaa.me/blog/post/9913083 which contains the code to allow dropping file which is first downloaded from the web or any different source (virtual one). I haven't change the code a bit but experience following problem. When dropping on desktop (or any other explorer location) I get following exception:

Invalid FORMATETC structure (Exception from HRESULT: 0x80040064 (DV_E_FORMATETC))

I'm not familiar with Interop objects so I found it quite difficult to solve. Maybe it is a problem of an environment I'm running the code. This is quite old code and I'm running it on Windows 10 and VS2019.

Please help me with solving that. Thanks.